Conventional injection sets each contain one sterilized injection needle and one needle protection sleeve slipped on it. Injection sets for medical purposes are traditionally contained in an external wrapper, one part of which is usually made of swedged plastics and the other is a tear-open paper cover. Packed in this wrapper is the injection needle which consists of the sharpened metallic needle and the plastic connection piece with an inner taper which fits the outer taper of the syringe point. Slipped on said needle is an inflexible plastic sheath, the needle protection sleeve, which is to protect the needle point from damage and to prevent injuries.
If the doctor proceeds "lege artis", i.e. strictly according to the rules of the medical profession, he will first take the needle still bearing the slipped-on needle protection sleeve out of the packing, then take a syringe out of its packing, break open the ampulla containing the liquid to be injected, then fit needle onto the syringe, remove the needle protection sleeve, fill the syringe with the ampulla contents via the needle, discard the used needle, take a new needle out of its packing, fit the needle and its protection sleeve onto the syringe, remove the protection sleeve and inject the syringe contents.
Besides this approach which is the proper technique according to the rules of the medical profession, several improper variants are also used which all have the following in common: While, on the one hand, they involve great health risks and are impractical, they are nevertheless time- and cost-saving on the other hand:
In a first variant, the needle used for filling the ampulla contents into the syringe is also used for the actual injection. This method has two disadvantages. First of all, if it is required to use a relatively thin injection needle, filling frequently not very fluid ampulla contents into a syringe is very time-consuming and cumbersome. Secondly, the needle point, which is very soft, will frequently become deformed upon contact with the ampulla bottom, a fact which will often go unnoticed by the doctor. As a result, the injection will clearly be more painful for the patient because considerably more structures in the fatty tissue of the skin and in the muscles, to some extent also nerve fibers or blood vessels, will be damaged both when the needle is inserted and when it is pulled out again. The greater extent of damage to the body tissue thus also involves a higher risk of bleedings as well as of injection abscesses and of a retrogradely intravascular application.
In a second variant, no needle is used for filling the ampulla contents into the syringe but the ampulla contents are sucked directly into the syringe via the syringe point. This approach holds a great health risk for the patient. This is due to the shortness of the syringe taper which only extends half a centimeter into the ampulla for which reason the ampulla has to be tilted together with the syringe to cause the ampulla contents to flow to the open end of the ampulla. Often a drop of the ampulla contents will exit the open end of the ampulla despite the fact that the syringe is filled at the same time. Such drop will adhere to the non-sterile ampulla exterior and, when the ampulla is tilted further at the end of the syringe filling operation, will eventually also be sucked into the syringe.
From a hygienic point of view, this is a severe mistake of the doctor which is at the root of the majority of injection abscesses with their fatal consequences. Nevertheless, statistics have shown that this method is more common among doctors and medical staff than the method according to the rules of the medical profession.
Consequently, it is the object of the present invention to provide an injection set of the aforementioned type which is of low cost and allows a perfectly hygienic use.